Wu Si-Ying, Park Gil-Yong, Kim So-Hee, Hulme John, An Seong Soo A
Department of BioNano Technology, Gachon BioNano Research Institute, Gachon University, Seongnam-si.
Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea.
Drug Des Devel Ther. 2016 Oct 14;10:3363-3378. doi: 10.2147/DDDT.S114832. eCollection 2016.
The aim of this study was to investigate the bacteriostatic and bactericidal effects of diminazene aceturate (DA) against five strains of pathogenic bacteria and two strains of nonpathogenic bacteria. The results showed that 5 μg/mL of DA suppressed the growth of pathogenic by as much as 77% compared with the controls. Enterohemorrhagic EDL933 (an O157:H7 strain) was the most sensitive to DA with a minimum inhibitory concentration of 20 μg/mL. Additional investigations showed that DA induced the highest level of intracellular reactive oxygen species in EDL933. A positive correlation between the reactive oxygen species levels and DA concentration was demonstrated. DA (5 μg/mL) was also a potent uncoupler, inducing a stationary phase collapse (70%-75%) in both strains of O157:H7. Further investigation showed that the collapse was due to the NaCl:DA ratio in the broth and was potassium ion dependent. A protease screening assay was conducted to elucidate the underlying mechanism. It was found that at neutral pH, the hydrolysis of H-Asp-pNA increased by a factor of 2-3 in the presence of DA, implying that DA causes dysregulation of the proton motive force and a decrease in cellular pH. Finally, a commercial verotoxin test showed that DA did not significantly increase toxin production in EDL933 and was a suitable antibacterial agent for Shiga-toxin-producing .
本研究的目的是调查乙酰马杜霉素（DA）对五株病原菌和两株非病原菌的抑菌和杀菌作用。结果表明，与对照组相比，5μg/mL的DA可使病原菌的生长抑制高达77%。肠出血性大肠杆菌EDL933（O157:H7菌株）对DA最为敏感，最低抑菌浓度为20μg/mL。进一步研究表明，DA在EDL933中诱导了最高水平的细胞内活性氧。活性氧水平与DA浓度之间呈正相关。DA（5μg/mL）也是一种有效的解偶联剂，在两株O157:H7菌株中均诱导了稳定期崩溃（70%-75%）。进一步研究表明，这种崩溃是由于肉汤中的NaCl:DA比例，并且依赖于钾离子。进行了蛋白酶筛选试验以阐明潜在机制。发现在中性pH值下，在DA存在的情况下，H-Asp-pNA的水解增加了2-3倍，这意味着DA导致质子动力势失调和细胞pH值降低。最后，一项商业维罗毒素试验表明，DA不会显著增加EDL933中的毒素产生，并且是一种适用于产志贺毒素大肠杆菌的抗菌剂。
